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Three-Dimensional Recording and Description of Motions of the Shoulder Mechanism
Abstract
A measurement technique is presented for recording positions of the bones of the shoulder mechanism, i.e., thorax, clavicula, scapula and humerus, in 3-D space, based on palpating and recording positions of bony landmarks. The palpation technique implies that only static positions can be measured. Accuracy of retrieving bony landmarks is checked on-line using rigid body assumptions. The measurement error is calculated afterwards and is comparable with cinegraphic methods. Axial rotation of the clavicula is estimated by minimizing rotations in the acromioclavicular joint. A number of motion definitions is compared by means of interindividual variation and subjective interpretability. Two useful definitions are proposed for describing motions of the shoulder mechanism. Four conditions have been recorded: abduction and anteflexion of the humerus both with and without additional weight in the hand. Abduction and anteflexion result in large differences in scapular and clavicular motions. The effect of additional weight in the hand on the position of the shoulder girdle is negligible.
... Protraction, a movement frequently associated with shoulder dysfunction, involves anterior movement, anterior tilt, and upward rotation. During glenohumeral elevation, the normal scapula demonstrates a pattern of upward rotation, external rotation, and posterior tilting (16). The predominant motion is upward rotation, and to a lesser degree external rotation and posterior tilt. ...
... The predominant motion is upward rotation, and to a lesser degree external rotation and posterior tilt. In addition, the scapula translates into a more superior and posterior position (16). Dynamic scapulohumeral rhythm depends on scapular motions and translations, combined with arm motion. ...
... However, these points don't guarantee the recording accuracy of the clavicle's motion. To address this problem, we employed a conventional method that involves minimizing the rotations of the AC joint [33]. The scapula possesses four bony landmarks, but these bony landmarks don't allow accurate tracking of its motion due to substantial displacements caused by skin and soft tissue motion. ...
... The APAS motion recording system was used to record the coordinates of the selected 16 bony landmarks to define the coordinate frames and the driving motion of the model components. The correction of the clavicle motion was calculated by reducing the rotations of the AC joint [33], while for the scapula, we used the solidification methodology described by [35] to correct their motion. The redundant force problem of the muscles, ligaments, and joints was implemented with two optimization methods, the GA and PSO methods. ...
An accurate model of the human upper limb is crucial for various applications, including prosthetic development, optimizing ergonomics, and rehabilitation. The novelty of this research is to obtain a model that predicts the forces of muscles, ligaments, and joint reactions under any loading conditions, thereby enabling the prediction of musculoskeletal forces during different daily activities. For this, a multibody three-dimensional dynamic model of the human upper limb is presented to study the upper limb musculoskeletal system. The model comprises 35 muscle elements, 11 ligaments, and 7 joints. Thirty equations of motion with 73 unknowns were obtained using Newton’s second law of motion. The Ariel Performance Analysis System ( APAS ) was utilized to record and analyze the motion of 16 bony landmarks using 8 digital video cameras with a sampling rate of 100 frames per second. The genetic algorithm (GA) and particle swarm optimization (PSO) are used to solve the redundant force problem of the model. The GA and PSO are implemented with two distinct objective functions; the first is the sum of the squared muscles’ stresses. The second one is the sum of the muscles’ energy consumption. The model was validated through EMG recordings of eight superficial muscles and with the available data in the literature. The results show that the inclusion of the ligaments at the GH and elbow joints in addition to the trapezoid and conoid ligaments in the model led to a more precise prediction of the muscles’ force. The PSO shows more accuracy and smoothness of the predicted muscles’ force, despite the GA taking more running time and requiring significant memory resources. The model also revealed that there is no great difference in the predicted muscles’ force when using any of the two cost functions.
... The shoulder joint was modeled as a ball and socket joint with three degrees of freedom. We recorded a combined movement of the glenohumeral and the scapulothoracic articulations [16,24]. As the motion-capture system calculates angles with respect to the segment coordinate system, lower values for joint deflection are calculated than visually estimated, especially at the shoulder girdle. ...
... This is another simplification, as the pronation and supination of the forearm are not only performed in the elbow, but in the proximal and distal radio-ulnar joints [25]. Wrist movement is characterized by movement between the hand and forearm segments, determined by a vector connecting the geometric wrist center and the calculated elbow center [16,24,26]. ...
Background: Internal rotation contractures of the shoulder are common sequelae of conservatively treated obstetric brachial plexus palsy (OBPP) with incomplete spontaneous neurological recovery. Humerus derotation osteotomy has been suggested as a possible treatment option to improve arm positioning. However, consensus as to whether humerus derotation osteotomy can successfully restore limb function is missing. Methods: In the present controlled cohort study, we aimed at analyzing global upper extremity kinematics with a 3D-video analysis system in children with shoulder internal rotation contractures secondary to OBPP before, and one year after, humerus derotation osteotomy. Patients under 18 years of age that presented to our center with conservatively treated internal rotation contractures of the shoulder and subsequently underwent humerus derotation osteotomy were included. The unimpaired arm served as a respective control. Results: Pre-operatively, all patients showed severe internal rotation contractures of the shoulder of almost 60° at rest. At the follow-up, the position of the shoulder at rest was greatly shifted to 9° of internal rotation. The patients showed statistically significant improvement in maximum external rotation and abduction of the shoulder, as well as in maximum flexion of the elbow, and the range of motion of pro/supination. The maximum internal rotation of the shoulder, however, was diminished after the osteotomy. Conclusions: Our data indicated that derotational osteotomy is a promising procedure which can be used to correct for internal rotation contractures secondary to OBPP. Moreover, 3D-video analysis proved to be a useful tool that supplies the surgeon with both precise information about the degree of distortion pre-operatively, thus helping to decide on the amount of correction, and secondly, a measurement of the post-operative gain in upper extremity function.
... First, the following landmarks were set to define the scapular plane: center of the glenoid (midpoint of a best-fit circle on an en-face view), medial root of scapular spine (trigonum scapulae) and the inferior angulus. (Fig. 3A-D) Then bony landmarks were set, which could be used in a clinical examination: (1) the angulus acromia [13] (AA), (2) the most apical point of the posterior acromioclavicular (AC)joint on the clavicular side [14], (3) and the most apical point located on a perpendicular line from the midpoint between the coracoid process tip (C) and the angulus acromii [15]. To determine the scapular axis, the marks of the glenoid and the medial root of the scapular spine are aligned on a parasagittal view and the inferior angulus is set vertically with 0° angle to mimic a neutral state. ...
... A study by Ludewig et al. [10] investigated historical and current local scapular coordinate systems. The angulus acromii (AA) is a commonly used landmark to reference scapular orientation [12,13]. Generally it is easily palpable even with thicker overlaying soft tissue and therefore suitable for detection of changes in scapular movement. ...
Background:
Scapulothoracic orientation, especially scapular internal rotation (SIR) may influence range of motion in reverse total shoulder arthroplasty (RTSA) and is subjected to body posture. Clinical measurements of SIR rely on apical bony landmarks, which depend on changes in scapulothoracic orientation, while radiographic measurements are often limited by the restricted field of view (FOV) in CT scans. Therefore, the goal of this study was (1) to determine whether the use of CT scans with a limited FOV to measure SIR is reliable and (2) if a clinical measurement could be a valuable alternative.
Methods:
This anatomical study analyzed the whole-body CT scans of 100 shoulders in 50 patients (32 male and 18 female) with a mean age of 61.2 ± 20.1 years (range 18; 91). (1) CT scans were rendered into 3D models and SIR was determined as previously described. Results were compared to measurements taken in 2D CT scans with a limited FOV. (2) Three apical bony landmarks were defined: (the angulus acromii (AA), the midpoint between the AA and the coracoid process tip (C) and the acromioclavicular (AC) joint. The scapular axis was determined connecting the trigonum scapulae with these landmarks and referenced to the glenoid center. The measurements were repeated with 0°, 10°, 20°, 30° and 40° anterior scapular tilt.
Results:
Mean SIR was 44.8° ± 5.9° and 45.6° ± 6.6° in the 3D and 2D model, respectively (p < 0.371). Mean difference between the measurements was 0.8° ± 2.5° with a maximum of 10.5°. Midpoint AA/C showed no significant difference to the scapular axis at 0° (p = 0.203) as did the AC-joint at 10° anterior scapular tilt (p = 0.949). All other points showed a significant difference from the scapular axis at all degrees of tilt.
Conclusion:
2D CT scans are reliable to determine SIR, even if the spine is not depicted. Clinical measurements using apical superficial scapula landmarks are a possible alternative; however, anterior tilt influenced by posture alters measured SIR.
... However, complex movements that combine multiple planes are difficult to express, especially shoulder movements due to the joint's high mobility. Over the years, many alternative conventions have been used or investigated to represent shoulder angles: attitude vector/quaternion (Woltring, 1994), cardan angles (Rab et al., 2002;van der Helm and Pronk, 1995;Wang et al., 1998), Euler angles (Davis et al., 1998;de Groot, 1997;van der Helm and Pronk, 1995;Wu et al., 2005), and the Globe system (An et al., 1991;Browne et al., 1990). All these methods seek yet somehow fail to represent shoulder angles in a way that is both (1) easily and correctly interpreted by practitioners; and (2) free of numerical instability such as gimbal lock (GL). ...
... However, complex movements that combine multiple planes are difficult to express, especially shoulder movements due to the joint's high mobility. Over the years, many alternative conventions have been used or investigated to represent shoulder angles: attitude vector/quaternion (Woltring, 1994), cardan angles (Rab et al., 2002;van der Helm and Pronk, 1995;Wang et al., 1998), Euler angles (Davis et al., 1998;de Groot, 1997;van der Helm and Pronk, 1995;Wu et al., 2005), and the Globe system (An et al., 1991;Browne et al., 1990). All these methods seek yet somehow fail to represent shoulder angles in a way that is both (1) easily and correctly interpreted by practitioners; and (2) free of numerical instability such as gimbal lock (GL). ...
Background: Kinematics is studied by practitioners and researchers in different fields of practice. It is therefore critically important to adhere to a taxonomy that explicitly describes positions and movements. However, current representation methods such as cardan and Euler angles fail to report shoulder angles in a way that is easily and correctly interpreted by practitioners, and that is free from numerical instability such as gimbal lock (GL). Methods: In this paper, we comprehensively describe the recent Tilt-Torsion (TT) method and compare it to the Euler YXY method currently recommended by the International Society of Biomechanics. While using the same three rotations as Euler YXY (plane of elevation, elevation, humeral rotation), TT reports humeral rotation independently from the plane of elevation. We assess how TT can be used to describe shoulder angles (1) in a simulated assessment of humeral rotation with the arm at the side, which constitutes a GL position, and (2) during an experimental functional task, with 10 wheelchair basketball athletes who sprint in straight line using a sports wheelchair. Findings: In the simulated GL experiment, TT provided both humeral elevation and rotation measurements, contrary to the Euler YXY method, despite both methods sharing the same GL positions. During the wheelchair sprints, humeral rotation ranged from 14{\deg} (externally) to 13{\deg} (internally), which is consistent with typical maximal ranges of humeral rotation, compared to 65{\deg} to 50{\deg} with the Euler YXY method. Interpretation: Based on our results, we recommend that shoulder angles be expressed using TT instead of Euler YXY.
... Hence, the axial rotation of the clavicle cannot be determined through non-invasive palpation measurements, but can be estimated on the basis of optimization techniques (Van der Helm and Pronk, 1995). In contrast to Van der Helm (1996), the use of the landmark AA is now proposed instead of the acromioclavicular joint (AC joint). ...
... Standardization implicates both parametrisation of the kinematics according to a well-defined protocol and description of the motions of theLCSs with respect to reference coordinate systems. Third, the method should allow for fast and easy to perform measurements, so it becomes possible to measure larger groups of individuals, (van der Helm andPronk 1995). ...
Manual wheelchair propulsion involves repetitive shoulder range of motion and muscular activities. It is an important form of mobility for many people with lower limb disabilities who depend upon their upper body to provide means of locomotion for completion of their activities of daily living. As a result of greater than normal usage of the upper limbs, shoulder and wrist pain and pathology are common among manual wheelchair users.
This study provides a biomechanical analysis of the manual wheelchair mobility in control subjects during their functional activities of daily living. Nonexperienced wheelchair users were recruited per this study for their feature of novice as they could determine their own self-selected speed and pattern of propulsion and to limit any variability that would be existed by a study group with multiple interindividual differences.
In the context of manual wheelchair propulsion, biomechanics of the upper body involves the study of how a manual wheelchair user imparts power to the wheels to achieve mobility. In general, the primary goal of biomechanical analysis of manual wheelchair propulsion is to generate knowledge that can be used to improve performance and/or prevent injuries.
The main objectives of this study were to investigate the impact of the trunk and upper limb biomechanics associated with diverse wheelchair configurations in terms of adjusting vertical displacement (seat-to-floor height) and horizontal displacement (rear wheel axle position). A marker-based 3D motion analysis technique was used with more recently to the six degrees of freedom (6DOF) analysis, as an integrated feature in the software that was used to collect the motion capture data (Qualisys Track Manager, QTM, Qualisys, Sweden). Three-dimensional kinematics of trunk and upper limb joints were investigated during physiological range of motion (ROM), activities of daily living (ADL), and functional wheelchair mobility that includes starting up from the rest, propulsion and stopping a wheelchair during manual propulsion.
The contribution of the shoulder complex muscles was investigated through the analysis of the surface electromyographic (sEMG) patterns of six stabilising muscles activity during the physiological range of motion, activities of daily living and functional wheelchair mobility. Also, the interrelationship between the users’ anthropometric characteristics and the biomechanics of their upper body were investigated in terms of kinematics, surface electromyography and spatiotemporal parameters during manual wheelchair propulsion.
This study showed an interrelationship between diverse wheelchair configurations of adjustable wheelchair rear wheel axle position and seat height and upper body kinematic behaviour, muscles recruitment and spatiotemporal patterns during manual wheelchair mobility. It was observed that changing rear wheel axle position posteriorly and raising the seat-to-floor distance (i.e. raising the seat height position) are correlated with higher upper body kinematics and release phase muscle activities and lower pushing patterns and push muscle activities during functional wheelchair mobility and so could be linked with a higher risk of musculoskeletal disorders.
As the number of manual wheelchair users is developing around the world, it becomes very essential to increase the understanding of the biomechanics of the upper body to enhance the performance and decrease the risk of injury. It is hoped that this knowledge will help both manufacturers and clinicians when designing and prescribing wheelchairs that are more proper to the users' functional features, needs and expectations, accordingly profiting users' independence and quality of life.
... Ren, et al. [38,39] used a 3D full-body model comprising 13 rigid segments (head, torso, pelvis, upper arms, forearms, thighs, shanks and feet) for ID analysis over the complete gait cycle. The anatomical coordinate systems of body segments were mainly adapted from Cappozzo, et al. [40] and van der Helm and Pronk [41]. The tri-axial ( ) and ( ) signals during SSP were directly calculated using Newton-Euler equations (Equations (1)-(6)). ...
... Ren, et al. [38,39] used a 3D full-body model comprising 13 rigid segments (head, torso, pelvis, upper arms, forearms, thighs, shanks and feet) for ID analysis over the complete gait cycle. The anatomical coordinate systems of body segments were mainly adapted from Cappozzo, et al. [40] and van der Helm and Pronk [41]. The tri-axial GRF(t) and GRM(t) signals during SSP were directly calculated using Newton-Euler equations (Equations (1)-(6)). ...
Monitoring natural human gait in real-life environments is essential in many applications, including quantification of disease progression, monitoring the effects of treatment, and monitoring alteration of performance biomarkers in professional sports. Nevertheless, developing reliable and practical techniques and technologies necessary for continuous real-life monitoring of gait is still an open challenge. A systematic review of English-language articles from scientific databases including Scopus, ScienceDirect, Pubmed, IEEE Xplore, EBSCO and MEDLINE were carried out to analyse the ‘accuracy’ and ‘practicality’ of the current techniques and technologies for quantitative measurement of the tri-axial walking ground reactions outside the laboratory environment, and to highlight their strengths and shortcomings. In total, 679 relevant abstracts were identified, 54 full-text papers were included in the paper and the quantitative results of 17 papers were used for meta-analysis and comparison. Three classes of methods were reviewed: (1) methods based on measured kinematic data; (2) methods based on measured plantar pressure; and (3) methods based on direct measurement of ground reactions. It was found that all three classes of methods have competitive accuracy levels with methods based on direct measurement of the ground reactions showing highest accuracy while being least practical for long-term real-life measurement. On the other hand, methods that estimate ground reactions using measured body kinematics show highest practicality of the three classes of methods reviewed. Among the most prominent technical and technological challenges are: (1) reducing the size and price of tri-axial load-cells; (2) improving the accuracy of orientation measurement using IMUs; (3) minimizing the number and optimizing the location of required IMUs for kinematic measurement; (4) increasing the durability of pressure insole sensors, and (5) enhancing the robustness and versatility of the ground reactions estimation methods to include pathological gaits and natural variability of gait in real-life physical environment.
... Thus, in this case, the time-variant bodyheading direction does not matter because the angle of the human body, an essential feature of the recognition model, is not less affected by the change of the body-heading orientation. To apply this method, the segment axes should be determined segment-by-segment through predefined joint movements, such as pronation-supination for the upper-limb joint [18] and flexion-extension for the lower-limb joint [19]. Moreover, the relation of segments with the global reference frame should be identified after estimating the relative pose of the sensor to the segment. ...
This study proposes a telemanipulation framework with two wearable IMU sensors without human skeletal kinematics. First, the states (intensity and direction) of spatial hand-guiding gestures are separately estimated through the proposed state estimator, and the states are also combined with the gesture’s mode (linear, angular, and via) obtained with the bi-directional LSTM-based mode classifier. The spatial pose of the 6-DOF manipulator’s end-effector (EEF) can be controlled by combining the spatial linear and angular motions based on integrating the gesture’s mode and state. To validate the significance of the proposed method, the teleoperation of the EEF to the designated target poses was conducted in the motion-capture space. As a result, it was confirmed that the mode could be classified with 84.5% accuracy in real time, even during the operator’s dynamic movement; the direction could be estimated with an error of less than 1 degree; and the intensity could be successfully estimated with the gesture speed estimator and finely tuned with the scaling factor. Finally, it was confirmed that a subject could place the EEF within the average range of 83 mm and 2.56 degrees in the target pose with only less than ten consecutive hand-guiding gestures and visual inspection in the first trial.
... In addition, Ludewig et al. [19] investigated the effects of elevation plane and angle on 3D shoulder joint motion and reported that the scapula rotates upward more in abduction than in flexion after 60° of elevation, with further differences as the elevation angle increases. Additionally, van der Helm and Pronk [20] reported that scapular upward rotation was significantly greater in abduction than in flexion, except in the early and final ranges of elevation, based on abduction and flexion shoulder joint motion analysis results. Particularly, the scapular motion has been shown to primarily depend on the hu- meral elevation plane. ...
Background:
Although visual examination and palpation are used to assess shoulder motion in clinical practice, there is no consensus on shoulder motion under dynamic and static conditions. This study aimed to compare shoulder joint motion under dynamic and static conditions.
Methods:
The dominant arm of 14 healthy adult males was investigated. Electromagnetic sensors attached to the scapular, thorax, and humerus were used to measure three-dimensional shoulder joint motion under dynamic and static elevation conditions and compare scapular upward rotation and glenohumeral joint elevation in different elevation planes and angles.
Results:
At 120° of elevation in the scapular and coronal planes, the scapular upward rotation angle was higher in the static condition and the glenohumeral joint elevation angle was higher in the dynamic condition (P<0.05). In scapular plane and coronal plane elevation 90°- 120°, the angular change in scapular upward rotation was higher in the static condition and the angular change in scapulohumeral joint elevation was higher in the dynamic condition (P<0.05). No differences were found in shoulder joint motion in the sagittal plane elevation between the dynamic and static conditions. No interaction effects were found between elevation condition and elevation angle in all elevation planes.
Conclusions:
Differences in shoulder joint motion should be noted when assessing shoulder joint motion in different dynamic and static conditions. Level of evidence: Level III, diagnostic cross-sectional study.
... Internal/external rotation movements reportedly do not change in a constant direction of rotation with increasing shoulder flexion angle but rather irregularly with internal/external rotation 13,[15][16][17][18][19] . Given the small angular change in the same movement 12,15) and the fact that the final limb position is the same in shoulder joint flexion and abduction, it is assumed that the same movement is performed in shoulder joint abduction, and the ambiguity of the movement may have affected the results. ...
[Purpose] This study aimed to validate whether scapular motion measured using a pad with retroreflective markers and optical motion analyzer (VICON MX) can reflect the motion calculated by images using multi-posture (gravity) magnetic resonance imaging. [Participants and Methods] The participants were 12 healthy males (12 dominant-side shoulders). The measurement items were the scapular angle at shoulder flexion 140° and 160° and abduction 100°, 120°, 140°, and 160°. The scapular angle changes were extracted from the upward/downward and internal/external rotations. Angular changes were calculated by subtracting the scapular angle in static position (drooped upper limb and external shoulder rotation) during resting chair sitting from the scapular angle in each of the six limb positions and subtracting it at shoulder abduction 100° from the scapular angle at shoulder abduction 120°, 140°, and 160°. [Results] The results showed no agreement in most cases and no consistent bias. [Conclusion] The result questions the validity of scapular motion analysis using pads with optical markers. However, the facility environment imposes many study limitations, and this method requires further validation eventually.
... Multiple methods of quantitative analysis have been proposed but have not been found to be clinically useful due to lack of consistent reliability, 44,45 limitation of data to one scapular kinematic component, 17,52,53,60 large error of the data in relation to actual bone motion, 18,32,58 or inability to use the assessment method(s) in a clinical setting due to inconveniences of cost and set-up (bone pins, electromagnetic tracking, and computed tomography scans). 28,29,38,41 As a result, even with the known limitations of qualitative analyses, 9,10 the visual observational method is still the most frequently selected by clinicians to identify the presence or absence of dyskinesis in the evaluation of the patient 26 and to make generalized assessments of change during the treatment process. ...
Background:
Scapula kinematics is recognized to be a crucial variable in shoulder dysfunction. Nevertheless, quantitative scapula tracking and measurement are not part of the current clinical evaluation. The main concern is measurement accuracy.
Methods:
To assess the accuracy of the wearable sensor technology Showmotion a cadaver experiment was designed, allowing a direct comparison between sensors directly pinned to the scapula and superficial sensors. A measurement protocol was adopted to evaluate errors in measurement, mimicking the suggested in vivo evaluation. Sensors were simultaneously placed above (supraspinal) and below (infraspinal) the scapular spine to determine if one placement resulted in fewer errors compared to the other.
Results:
Mean and standard deviations of the supraspinal sensor root mean square error (RMSE) in flexion-extension movements resulted in 3.59° ± 2.36°, 4.73° ± 2.98°, and 6.26° ± 3.62° for upward-downward rotation (up-down), anterior-posterior tilt and internal-external (intra-extra) rotation, respectively, while 2.16° ± 1.21°, 2.20° ± 1.02°, and 4.46° ± 2.16° for the infraspinal sensor. In abduction-adduction movements, mean and standard deviations of the supraspinal sensor RMSE resulted in 4.26° ± 2.98°, 5.68° ± 4.22°, and 7.04° ± 4.36° for up-down rotation, anterior-posterior tilt, and intra-extra rotation, respectively, while 2.38° ± 1.63°, 2.47° ± 1.77°, and 4.92° ± 3.14° for the infraspinal sensor. The same behavior was confirmed in shrug movements, where 4.35° ± 3.24°, 4.63° ± 3.09°, and 5.34° ± 6.67° are mean and standard deviations of the supraspinal sensor RMSE for up-down rotation, anterior-posterior tilt, and intra-extra rotation, respectively, while 2.76° ± 1.87°, 2.83° ± 2.53°, and 4.68° ± 5.22° for the infraspinal sensor.
Conclusion:
This method of quantitative assessment of scapular motion is shown to have good accuracy and low error between the sensor measurements and actual bone movement in multiple planes of scapular motion, both over the entire range of motion and in its individual segment intervals. The decreased amount of error with the infraspinal sensor placement suggests that placement is ideal for clinical quantitative assessment of scapular motion.
... The scapula demonstrates a pattern of upward rotation, external rotation, and posterior tilting during glenohumeral elevation. The three-dimensional analysis of scapular motion by van der Helm and Pronk describe scapular upward rotation occurring about an anterior-posterior axis, with the inferior angle of the scapula moving laterally; [10] external rotation occurring about a superior-inferior axis, with the lateral border of the scapula moving posteriorly; posterior tilt occurring about a mediallateral axis, with the inferior angle moving anteriorly. ...
Rotator Cuff tendinopathy (RCT) is a common disorder that poses challenges for effective treatment. Evidence suggests that extrinsic, intrinsic, and combinations of biomechanical mechanisms play a role. There are no significant differences in outcome between conservatively and surgically treated patients with subacromial impingement syndrome (SAIS). For most patients with subacromial impingement syndrome (SAIS), nonsurgical treatment is successful. Surgical intervention is successful in patients who fail nonsurgical treatment. Surgeon experience and intraoperative assessment may guide the method of surgical treatment. Studies have shown that many surgical interventions, including debridement and open and arthroscopic acromioplasty, have been successful. However, there remains a need for high-quality clinical research on the diagnosis and treatment of SAIS. In this review, there are not figures and outcomes.
... The angulus acromii (AA) is a commonly used landmark to reference scapular orientation. (10,11) Generally it is easily palpable even with thicker overlaying soft tissue and therefore suitable for detection of changes in scapular movement. However, our study shows that SIR is underestimated by around 19° when scapular tilt is at 0°. ...
Background
Scapulothoracic orientation, especially scapular internal rotation (SIR) may influence range of motion in reverse total shoulder arthroplasty (RTSA) and is subjected to body posture. Clinical measurements of SIR rely on apical bony landmarks which are subjected to changes in scapulothoracic orientation, while radiographic measurements are often limited by the restricted field of view (FOV) in CT scans. Therefore, the goal of this study was (1) to determine whether the use of CT scans with a limited FOV to measure SIR is reliable and (2) if a clinical measurement could be a valuable alternative.
Methods
This anatomical study analyzed the whole-body CT-scans of 100 shoulders in 50 patients (32 male and 18 female) with a mean age of 61.2 ± 20.1 years (range 18; 91). (1) CT-scans were rendered into 3D models and SIR was determined as previously described. Results were compared to measurements taken in 2D CT-scans with a limited FOV. (2) Three apical bony landmarks were defined: (the angulus acromii (AA), the midpoint between the AA and the coracoid process tip (C) and the acromioclavicular (AC) joint. The scapular axis was determined connecting the trigonum scapulae with these landmarks and referenced to the glenoid center. The measurements were repeated with 0°, 10°, 20°, 30° and 40° anterior scapular tilt.
Results
Mean SIR was 44.8° ± 5.9° and 45.6° ± 6.6° in the 3D and 2D model, respectively (p < 0.371). Mean difference between the measurements was 0.8°± 2.5° with a maximum of 10.5°. A Bland-Altman-Plot showed 5% outliers. Midpoint AA/C showed no significant difference to the scapular axis at 0° (p = 0.203) as did the AC joint at 10° anterior scapular tilt (p = 0.949). All other points showed a significant difference from the scapular axis at all degrees of tilt.
Conclusion
2D CT-scans are reliable to determine SIR, even if the spine is not depicted. Position of the patient in the CT scanner needs to be considered and supine positioning presents a limitation. Clinical measurements using apical superficial scapula landmarks are a possible alternative, however anterior tilt influenced by posture alters measured SIR.
... An appropriate compromise between simplicity and realism should be made to construct a kinematic linkage of human body. Van der Helm and Pronk (1995) presented a complete quantitative description of motions of shoulder mechanism, but their recording method was based on a static 3D digitizer called "palpator" and their shoulder kinematic model is too complex for ergonomic, human behavioral and athletic performance studies. For these applications, human joints are often simplified as three degrees of freedom (3-DOF) spherical, 2-DOF universal or 1-DOF revolute joints. ...
Introduction In clinical, ergonomic, human behavioral and athletic performance studies, three-dimensional human movements are recorded most frequently by an optical system. The kinematics of the human body is calculated from external surface marker positions. These surface marker positions are measured directly by the optical system. But how the internal kinematic linkage of the human body can be constructed from surface markers is an open question. Apart from direct measurement errors and skin movement relative to underlying bone, another difficulty arises from the simplification of a complex articular joint into a mechanical joint. An appropriate compromise between simplicity and realism should be made to construct a kinematic linkage of human body. Van der Helm and Pronk (1995) presented a complete quantitative description of motions of shoulder mechanism, but their recording method was based on a static 3D digitizer called "palpator" and their shoulder kinematic model is too complex for ergonomic, human behavioral and athletic performance studies. For these applications, human joints are often simplified as three degrees of freedom (3-DOF) spherical, 2-DOF universal or 1-DOF revolute joints. The relative translational joint movement is generally neglected. Engin and co-workers(1989) treated the shoulder complex motion range, but the problem of how to locate of the joint center remained obscure. Again, their recording method was a static one. Surprisingly, there are few studies in which the quantitative description of the kinematic linkage of the upper limb resulted from an electro-optical recording method. Under the context of research of the human motor strategy, the shoulder complex is simplified into two joints in the present study: one connecting the sternum to the clavicle (sternoclavicular joint) and the other connecting the clavicle to the humerus (glenohumeral joint). The sternoclavicular joint is modeled as a 2-DOF universal joint, and the glenohumeral joint is modeled as a ball-and-socket 3-DOF joint. Under this simplification, the glenohumeral joint center will be quantitatively located with respect to external surface marker positions. The location of the elbow flexion-extension axis and the elbow center obtained are also examined in this paper.
... Glenohumeral rotation center estimation via using the regression method presented by Meskers et al. (1997) The regression model for estimation of the glenohumeral rotation center (GH(MESK)) presented by Meskers et al. (1997) requires five landmarks on each scapula bone as coefficients and several distances among them. The required anatomical landmarks are summarized in Table 6 and can be, according to Meskers et al. (1997, p. 93), obtained by numerous palpation techniques (Johnson, Stuart, & Mitchell, 1993;Meskers, Vermeulen, de Groot, van der Helm, & Rozing, 1998;van der Helm & Pronk, 1995). For the regression method the origin Meskers et al. (1997, p. 95 Meskers et al. (1997, p. Meskers et al. (1997, p. 95 Meskers et al. (1997, p (Meskers et al., 1997, p. 95 (Meskers et al., 1997, p. 95 (Meskers et al., 1997, p. 95 (Table 18) and can be enabled by setting the boolean USE_MESKERS_GH_ESTIMATION statement to one. ...
Background: Musculoskeletal (MSK) models allow a broad applicability in various scientific, health related and industrial fields. Commonly, model individualization can be realized either by rescaling the generic reference model, to match a specific subject, based on body-segment anthropometry, joint geometry, and muscle-tendon attachment sites. Alternatively, MSK information can be directly extracted from personal medical images. Though, most MSK-models still depend on linear segment-wise scaling methods (LSM), like the length-mass-fat scaling law. Few developments in functional (KSM) and anatomical scaling approaches (ALSM) have been lately applied to the lower extremities.
Objective: The aim of the present work is to enable the extension of both advanced non-linear scaling approaches (ALSM and KSM) by implementing an upper body stick-figure sub-model. Both scaling approaches initially require a stick-figure representation of the individual subject for the process of model scaling and kinematic analysis.
Methods: A 14 segment upper body stick-figure model was developed on top of a preexisting lower extremity model. Based on the current literature, scaling approaches, joint center estimations and movement constraints were applied to the model. Further kinematic multibody optimizations were prepared for prospective implementation. Kinematic outcomes of the elbow joint were compared between an existing linear scaled model and the newly developed model.
Results: For all trials, the bilateral elbow joint angle outputs of the stick-figure model (SFM) were significantly correlated to the outputs of the LSM model (p < 0.001). Highest value of R² was observed for the left elbow with 92%, for the right elbow with 100%. Lowest R² value was observed for the left elbow with 44% and for the right elbow with 31%. Lowest RSME was observed with a val-ue of 5°. Highest RMSE was observed with a value of 245°.
Conclusion: The newly developed model allows the prospective extension of advanced non-linear scaling approaches to the extremities of the upper body. The model is directly created from anatomical landmarks of a specific subject. Further improvements by functional methods are presented in detail. These methods may positively conclude to the estimation of joint center locations, scaling approaches and kinematic simulations.
... The comparable contribution between acromioclavicular UR and sternoclavicular posterior rotation suggests that the scapula and clavicle now function as a mechanism, but do not fully become a single "claviscapular link," as proposed by Dvir and Berme 23 and modeled by van der Helm. 1,2,25 However, with the scapula and clavicle more coupled, the clavicle may be able to fulfill its role as a strut by supporting the upper limb on the thorax. 39 This function may be especially critical in higher phases of motion because of the higher dynamic loads between 60 and 120 degrees of humerothoracic elevation. ...
Background:
Scapulothoracic upward rotation (UR) is an important shoulder complex motion allowing for a larger functional work space and improved glenohumeral muscle function. However, the kinematic mechanisms producing scapulothoracic UR remain unclear, limiting the understanding of normal and abnormal shoulder movements.
Objective:
The objective of this study was to identify the coupling relationships through which sternoclavicular and acromioclavicular joint motions contribute to scapulothoracic UR.
Design:
This was a cross-sectional observational study.
Methods:
Sixty participants were enrolled in this study; 30 had current shoulder pain, and 30 had no history of shoulder symptoms. Shoulder complex kinematics were quantified using single-plane fluoroscopy and 2D/3D shape matching and were described as finite helical displacements for 30-degree phases of humerothoracic elevation (30°-60°, 60°-90°, and 90°-120°). A coupling function was derived to estimate scapulothoracic UR from its component motions of acromioclavicular UR, sternoclavicular posterior rotation, and sternoclavicular elevation as a function of acromioclavicular internal rotation. The proportional contributions of each of the component motions were also calculated and compared between phases of humerothoracic elevation and groups.
Results:
Scapulothoracic UR displacement could be effectively predicted using the derived coupling function. During the 30- to 60-degree humerothoracic elevation phase, acromioclavicular UR accounted for 84.2% of scapulothoracic UR, whereas sternoclavicular posterior rotation and elevation each accounted for <10%. During later phases, acromioclavicular UR and sternoclavicular posterior rotation each accounted for 32%-42%, whereas sternoclavicular elevation accounted for <11%.
Limitations:
Error due to the tracking of sternoclavicular posterior rotation may have resulted in an underprediction of its proportional contribution and an overprediction of the proportional contribution of acromioclavicular UR.
Conclusions:
Acromioclavicular UR and sternoclavicular posterior rotation are the predominant component motions of scapulothoracic UR. More research is needed to investigate how these coupling relationships are affected by muscle function and influenced by scapular dyskinesis.
... The ISB recommends a symmetric Euler sequence, YXY, for reporting HT kinematics [66]. Although Euler angles are popular due to their intuitive nature, they present limitations due to their numerical instabilities, temporal nature and interaction issues [70]. Numerical instabilities or gimbal lock occurs at θ 2 = ± π 2 for Cardan angles and at θ 2 = 0, ±π for Euler angles. ...
In this survey, we review the field of human shoulder functional kinematic representations. The central question of this review is to evaluate whether the current approaches in shoulder kinematics can meet the high-reliability computational challenge. This challenge is posed by applications such as robot-assisted rehabilitation. Currently, the role of kinematic representations in such applications has been mostly overlooked. Therefore, we have systematically searched and summarised the existing literature on shoulder kinematics. The shoulder is an important functional joint, and its large range of motion (ROM) poses several mathematical and practical challenges. Frequently, in kinematic analysis, the role of the shoulder articulation is approximated to a ball-and-socket joint. Following the high-reliability computational challenge, our review challenges this inappropriate use of reductionism. Therefore, we propose that this challenge could be met by kinematic representations, that are redundant, that use an active interpretation and that emphasise on functional understanding.
... Considering the humerus movement, the total degree of freedom of the shoulder is up to 7. However, in the process of activity of the shoulder, the rotation of the clavicle around its axis is very small and it has an internal DoF that does not change the whole posture of link 4 [19][20][21]. Therefore, for joint a, the rotation in the direction of the winding of component 2 is an extra freedom. ...
Rehabilitation robotics has become a widely accepted method to deal with the training of people with motor dysfunction. In robotics medium training, shoulder repeated exercise training has been proven beneficial for improving motion ability of human limbs. An important and difficult paradigm for motor function rehabilitation training is the movement rhythm on the shoulder, which is not a single joint but complex and ingenious combination of bones, muscles, ligaments, and tendons. The most robots for rehabilitation were designed previously considering simplified biomechanical models only, which led to misalignment between robots and human shoulder. Current biomechanical models were merely developed for rehabilitation robotics design. This paper proposes a new hybrid spatial model based on joint geometry constraints to describe the movement of the shoulder skeletal system and establish the position analysis equation of the model by a homogeneous coordinate transformation matrix and vector method, which can be used to calculate the kinematics of human-robot integrated system. The shoulder rhythm, the most remarkable particularity in shoulder complex kinematics and important reference for shoulder training strategy using robotics, is described and analyzed via the proposed skeleton model by three independent variables in this paper. This method greatly simplifies the complexity of the shoulder movement description and provides an important reference for the training strategy making of upper limb rehabilitation via robotics.
... Le repère local du bassin est basé sur le repère présenté en Figure 2.6 de Leardini et al. (1999). Ceux des deux épaules sont basés sur les recommandations de « l'International Shoulder Group » (van der Helm and Pronk (1995)). Tous les repères locaux sont des repères orthonormés directs dont : ...
La première cause de handicap neurologique chez l’adulte en France est l’accident vasculaire cérébral (AVC). L’AVC est la principale cause de l’hémiplégie et peut conduire à des séquelles lourdes telles que des difficultés à se lever et s’asseoir. A ce jour, il n’existe pas de dispositif d’aide au passage assis-debout (PAD)/debout-assis (PDA) permettant le déplacement en position debout adapté aux sujets hémiplégiques.La conception de ce type de dispositif est l’objectif du projet VHIPOD. L’absence d’études sur le PAD/PDA avec aide des sujets hémiplégiques invite à explorer deux types d’aides : ancrage fixe et ancrage mobile. Une première campagne d’expérimentation a permis de mesurer le PAD/PDA de 18 sujets sains et 11 sujets hémiplégiques droits dans différentes conditions : avec/sans ancrage fixe, avec/sans écharpe d’immobilisation et pour différentes positions de l’ancrage fixe. Ce travail a permis de montrer la contribution d’un ancrage fixe sur le PAD/PDA (ex. réduction des moments articulaires aux genoux) et de montrer que la position de l’ancrage fixe influence le PAD/PDA (ex. une position du côté gauche/sain augmente l’appui sur le membre inférieur gauche). Une deuxième campagne d’expérimentation a permis de mesurer le PAD/PDA avec ancrage mobile de 7 sujets sains et 10 sujets hémiplégiques gauches. Ce travail a permis d’identifier la différence entre les sujets hémiplégiques et les sujets sains (ex. les sujets hémiplégiques gauches sont plus asymétriques que les sujets sains) et de comparer les résultats du PAD/PDA avec ancrage mobile à ceux du PAD/PDA avec ancrage fixe (ex. l’asymétrie des sujets hémiplégiques est augmentée pour le PAD/PDA avec ancrage mobile.
... Motion data was converted to LCS of the thorax, scapula, humerus and forearm according to the ISB guidelines ( Wu et al., 2005), with exception of a deviating LCS definition of the clavicle. This was done to account for axial rotation of the SC joint, under the assumption of minimal AC rotation (van der Helm and Pronk, 1995). The LCS of the clavicula was defined as: z-axis as vector from the SC joint to ACD; the y-axis as the vector perpendicular to the plane formed by ACD, ACV and SC, pointing cranially and the x-axis as the vector perpendicular to the y-axis and z-axis, pointing ventrally. ...
Background:
Altered scapular kinematics have been associated with shoulder pain and functional limitations. To understand kinematics in persons with spinal cord injury during manual handrim wheelchair propulsion, a description of normal scapular behaviour in able-bodied persons during this specific task is a prerequisite for accurate interpretation. The primary aim of this study is to describe scapular kinematics in able-bodied persons during manual wheelchair propulsion.
Methods:
Sixteen able-bodied, novice wheelchair users without shoulder complaints participated in the study. Kinematic and kinetic data were collected during a standardized pose in the anatomic posture, frontal-plane arm elevation and low-intensity steady-state handrim wheelchair propulsion and upper-body Euler angles were calculated.
Findings:
Scapulothoracic joint orientations in a static position were 36.7° (SD 5.4°), 6.4° (SD 9.1°) and 9.1° (SD 5.7°) for respectively protraction, lateral rotation and anterior tilt. At 80° of arm elevation in the frontal plane, the respective values of 33.4° (SD 8.0°), 23.9° (SD 5.4°) and 4.1° (SD 11.3°) were found. During the push phase of manual wheelchair propulsion, the mean scapular rotations were respectively 32.7° (SD 7.1°), 7.1° (SD 9.2°) and 9.8° (SD 8.3°).
Interpretation:
The orientation of the scapula in a static pose, during arm elevation and in manual wheelchair propulsion in able-bodied participants showed similar patterns to a previous study in persons with para- and tetraplegia. These values provide a reference for the investigation of the scapular movement pattern in wheelchair-dependent persons and its relation to shoulder complex abnormalities.
... Given that there are no previous in vivo studies analyzing the influence of load on thoracohumeral movement, these data cannot be directly compared with previous results. However, considering the scapula as part of the thoracohumeral movement, our results are consistent with previous studies that reported an influence of handheld weight on scapular kinematics [17,39]. ...
Obtaining kinematic patterns that depend on the shoulder injury may be important when planning rehabilitation. The main goal of this study is to explore whether the kinematic patterns of continuous and repetitive shoulder elevation motions are different according to the type of shoulder injury in question, specifically tendinopathy or rotator cuff tear, and to analyze the influence of the load handled during its assessment. For this purpose, 19 individuals with tendinopathy and 9 with rotator cuff tear performed a repetitive scaption movement that was assessed with stereophotogrammetry. Furthermore, static range of motion (ROM) and isometric strength were evaluated with a goniometer and a dynamometer, respectively. Dynamic measurements of maximum elevation (Emax), variablility of the maximum angle (VMA), maximum angular velocity (Velmax), and time to maximum velocity (tmaxvel) were found to be significantly different between the tendinopathy group (TG) and the rotator cuff tear group (RTCG). No differences were found in the ROM assessed with goniometry and the isometric strength. The effect of increasing the load placed in the hand during the scaption movement led to significant differences in Emax, VMA, tmaxvel and repeatability. Therefore, only the dynamic variables showed sufficient capability of detecting differences in functional performance associated with structural shoulder injury. The differences observed in the kinematic variables between patients with tendinopathy and rotator cuff tear seem to be related to alterations in thoracohumeral rhythm and neuromuscular control. Kinematic analysis may contribute to a better understanding of the functional impact of shoulder injuries, which would help in the assessment and treatment of shoulder pain.
... Therefore, the activity of right upper trapezius muscle is increased in the DHF posture. Second, the DHF posture involves 30° of scapulothoracic upward rotation through a synchronous 20 to 25° of clavicular elevation at the sternoclavicular joint 13) . The scalene muscle inserts at the first and second ribs and elevates the ribcage 14) . ...
[Purpose] This study investigated the effect of sleep posture on neck muscle activity. [Subjects and Methods] The study recruited 20 healthy subjects, who were positioned in three supine sleeping positions: both hands at sides, both hands on the chest, and dominant hand on the forehead. The activities of the scalene and upper trapezius muscles bilaterally were measured by surface electromyography. [Results] The upper trapezius and scalene muscle activity on the right side was significantly greater in the supine with dominant hand on the forehead position than in the other positions. [Conclusion] Sleep posture is important and prevent neck and shoulder musculoskeletal pain.
... Wu et al 19 suggest that this can be estimated using the optimization technique shown by Van der Helm and Pronk. 14 The aim of this study was to propose a procedure to describe clavicular motion in 3 dimensions (3D) using direct measurements of bone and 3 transcortical pins in the clavicle. ...
Background:
For many years, researchers have attempted to describe shoulder motions by using different mathematical methods. The aim of this study was to describe a procedure to quantify clavicular motion.
Methods:
The procedure proposed for the kinematic analysis consists of 4 main processes: 3 transcortical pins in the clavicle, motion capture, obtaining 3-dimensional bone models, and data processing.
Results:
Clavicular motion by abduction (30° to 150°) and flexion (55° to 165°) were characterized by an increment of retraction of 27° to 33°, elevation of 25° to 28°, and posterior rotation of 14° to 15°, respectively. In circumduction, clavicular movement described an ellipse, which was reflected by retraction and elevation. Kinematic analysis shows that the articular surfaces move by simultaneously rolling and sliding on the convex surface of the sternum for the 3 movements of abduction, flexion, and circumduction.
Conclusion:
The use of 3 body landmarks in the clavicle and the direct measurement of bone allowed description of the osteokinematic and arthrokinematic movement of the clavicle.
... However, clavicle axial rotation can hardly be measured due to STA, which raises the question of the legitimacy of modelling this clavicle DoF. Furthermore, most of the experimental studies do not attempt to measure this DoF ( de Groot and Brand, 2001), while some try to assess axial rotation through optimisations either by minimising the acromioclavicular rotations (van der Helm and Pronk, 1995) The modelling choice of the scapulothoracic joint which consists in defining contact points of the scapula on an ellipsoid representing the thorax is widespread. However, there is no consensus on the number and location of the contact points. ...
Soft tissue artefact (STA), i.e. the motion of the skin, fat and muscles gliding on the underlying bone, may lead to a marker position error reaching up to 8.7 cm for the particular case of the scapula. Multibody kinematic optimisation (MBO) is one of the most efficient approaches used to reduce STA. It consists in minimising the distance between the positions of experimental markers on a subject skin and the simulated positions of the same markers embedded on a kinematic model. However, the efficiency of MBO directly relies on the chosen kinematic model. This paper proposes an overview of the different upper limb models available in the literature and a discussion about their applicability to MBO.
... Numerous groups have analysed human shoulder movements with imaging techniques (Freedmann and Munro 1966;Doody et al. 1970;Soslowsky et al. 1992) and with non-invasive motion recording techniques (Baag and Forrest 1988; Culham and Peat 1993;van der Helm and Pronk 1995;De Groot et al. 1999;Lenarcic and Stanisic 2003). The shoulder analysis in this paper is based on a methodology introduced by Moeslund et al. (2005), which allows to simplify and quantify human shoulder movement. ...
Rehabilitation robots have become important tools in stroke rehabilitation. Compared to manual arm training, robot-supported training can be more intensive, of longer duration and more repetitive. Therefore, robots have the potential to improve the rehabilitation process in stroke patients. Whereas a majority of previous work in upper limb rehabilitation robotics has focused on end-effector-based robots, a shift towards exoskeleton robots is taking place because they offer a better guidance of the human arm, especially for movements with a large range of motion. However, the implementation of an exoskeleton device introduces the challenge of reproducing the motion of the human shoulder, which is one of the most complex joints of the body. Thus, this paper starts with describing a simplified model of the human shoulder. On the basis of that model, a new ergonomic shoulder actuation principle that provides motion of the humerus head is proposed, and its implementation in the ARMin III arm therapy robot is described. The focus lies on the mechanics and actuation principle. The ARMin III robot provides three actuated degrees of freedom for the shoulder and one for the elbow joint. An additional module provides actuated lower arm pro/supination and wrist flexion/extension. Five ARMin III devices have been manufactured and they are currently undergoing clinical evaluation in hospitals in Switzerland and in the United States.
... The current standard involves the measurement of the passive and active range of motion of an extremity in a single plane or functional movements (which are better related to activities of daily living) [174] using conventional measurements [175] (e.g. goniometry, tape measures, inclinometer) or 3D motion analysis [174,176,177]. The Faciometer (University of Vienna) measures the ranges of mimic movements, e.g. the distance between the tragus and the mouth using calipers and an electronic display [178]. ...
Background:
Problematic scarring remains a challenging aspect to address in the treatment of burns and can significantly affect the quality of life of the burn survivor. At present, there are few treatments available in the clinic to control adverse scarring, but experimental pharmacological anti-scarring strategies are now beginning to emerge. Their comparative success must be based on objective measurements of scarring, yet currently the clinical assessment of scars is not carried out systematically and is mostly based on subjective review of patients. However, several techniques and devices are being introduced that allow objective analysis of the burn scar. The aim of this article is to evaluate various objective measurement tools currently available and recommend a useful panel that is suitable for use in clinical trials of anti-scarring therapies.
Methods:
A systematic literature search was done using the Web of Science, PubMed and Cochrane databases. The identified devices were then classified and grouped according to the parameters they measured. The tools were then compared and assessed in terms of inter- and intra-rater reproducibility, ease of use and cost.
Results:
After duplicates were removed, 5062 articles were obtained in the search. After further screening, 157 articles which utilised objective burn scar measurement systems or tools were obtained. The scar measurement devices can be broadly classified into those measuring colour, metric variables, texture, biomechanical properties and pathophysiological disturbances.
Conclusions:
Objective scar measurement tools allow the accurate and reproducible evaluation of scars, which is important for both clinical and scientific use. However, studies to evaluate their relative performance and merits of these tools are scarce, and there remain factors, such as itch and pain, which cannot be measured objectively. On reviewing the available evidence, a panel of devices for objective scar measurement is recommended consisting of the 3D cameras (Eykona/Lifeviz/Vectra H1) for surface area and volume, DSM II colorimeter for colour, Dermascan high-frequency ultrasound for scar thickness and Cutometer for skin elasticity and pliability.
... Note that, as a first step, the position, velocity, and acceleration vectors of the upper limb bodies were computed assuming an ideal spherical GH joint. The axial orientation of the clavicle was estimated by minimizing the AC joint rotations [36] . ...
Kinematically unconstrained biomechanical models of the glenohumeral (GH) joint are needed to study the GH joint function, especially the mechanisms of joint stability. The purpose of this study is to develop a large-scale multibody model of the upper limb that simulates the 6 degrees of freedom (DOF) of the GH joint and to propose a novel inverse dynamics procedure that allows the evaluation of not only the muscle and joint reaction forces of the upper limb but also the GH joint translations. The biomechanical model developed is composed of 7 rigid bodies, constrained by 6 anatomical joints, and acted upon by 21 muscles. The GH joint is described as a spherical joint with clearance. Assuming that the GH joint translates according to the muscle load distribution, the redundant muscle load sharing problem is formulated considering as design variables the 3 translational coordinates associated with the GH joint translations, the joint reaction forces associated with the remaining kinematic constraints, and the muscle activations. For the abduction motion in the frontal plane analysed, the muscle and joint reaction forces estimated by the new biomechanical model proposed are similar to those estimated by a model in which the GH joint is modeled as an ideal spherical joint. Even though this result supports the assumption of an ideal GH joint to study the muscle load sharing problem, only a 6 DOF model of the GH joint, as the one proposed here, provides information regarding the joint translations. In this study, the biomechanical model developed predicts an initial upward and posterior migration of the humeral head, followed by an inferior and anterior movement, which is in good agreement with the literature.
... The dynamic tracking of the scapula was accomplished through the methodology of Senk and Chèze [26]. For the definition of the humerus orientation, the GH joint center was estimated using the algorithm of Gamage and Lasenby [10], while, for the clavicle, its axial orientation was estimated through the minimization of the AC joint rotations [32]. ...
The application of musculoskeletal models to estimate muscle and joint reaction forces usually requires optimization strategies, regardless of using inverse or forward dynamics approaches. Most studies combined inverse dynamics and Static Optimization (SO) to solve the redundant muscle force distribution problem. However, the SO does not allow the simulation of time-dependent physiological criteria or of the time-dependent physiological nature of muscles. The Extended Inverse Dynamics (EID), which solves all instants of time simultaneously, was proposed to overcome these limitations of the SO, but the feasibility of this procedure is limited by the size of the optimization problem that can be realistically considered. This work proposes a new method that overcomes the aforementioned limitations of the SO and EID, i.e., that is able to handle time-dependent physiological criteria and has no limitations on the size of the problem to be solved. The proposed procedure, named here Window Moving Inverse Dynamics Optimization (WMIDO), consists in considering a moving window with the size of k instants of time in which the muscle force distribution problem is solved. The window moves iteratively across all instants of time until the muscle force distribution problem has been solved. The SO, EID, and WMIDO are applied to solve an upper limb abduction in the frontal plane, for which results are widely available in the literature, to demonstrate that similar optimal solutions are obtained for a time-independent physiological criterion if the redundant problem is not too large. Although the WMIDO is not as efficient as the SO for the type of problem tested, it is significantly faster than the EID. Moreover, the WMIDO is able to solve the motion under analysis regardless of the discretization level considered, whereas the EID fails due to memory limitations. Overall, the results show the WMIDO as a viable alternative to the current optimization procedures based on inverse dynamics.
Background
Acromioclavicular joint (ACJ) disruption occurs frequently in athletes engaged in contact sports. However, the current understanding of ACJ biomechanics during muscle-driven functional activities and the influence of different treatment approaches (eg, reconstruction surgery vs nonoperative methods) on ACJ kinematics and stability remains limited. The absence of precise in vivo biomechanical measurement modalities for scapular and clavicular kinematics contributes significantly to this lack of understanding.
Purposes/Hypothesis
The purposes of this study were to determine whether dynamic stereo x-ray (DSX) imaging can be used to evaluate the in vivo kinematics of the ACJ and to provide preliminary comparative data on ACJ kinematics, range of motion, and isometric strength of surgically reconstructed or nonoperatively treated ACJ shoulders and their uninjured contralateral shoulders. It was hypothesized that ACJ kinematics could be measured successfully using DSX and that surgically and nonoperatively treated shoulders would show abnormal 3-dimensional (3-D) ACJ kinematics compared with the uninjured contralateral.
Study Design
Controlled laboratory study.
Methods
In this cross-sectional study, 11 participants who had undergone unilateral ACJ reconstruction surgery and 3 patients who received nonoperative treatment were enrolled. ACJ kinematics were assessed during active forward flexion, scaption, and abduction through high-speed DSX imaging, complemented by 3-D bone models obtained via computed tomography (CT) scans. To gauge kinematic differences, a 1-dimensional statistical parametric mapping method was employed, which compared outcomes in the index limb to those in the uninjured counterpart. In addition, the range of motion and isometric strength at various abduction angles were analyzed, employing a repeated-measures analysis of variance to compare the affected and uninjured sides.
Results
Leveraging a combination of DSX imaging and patient-specific CT bone models, ACJ kinematics was measured successfully during movements along anatomic planes. Preliminary findings from this investigation revealed no detectable differences between the surgically reconstructed and uninjured sides in ACJ biomechanics, shoulder range of motion, and isometric strength outcomes. However, on average, the nonoperatively treated shoulders demonstrated increased internal rotation, upward rotation, and posterior tilting of the scapula relative to the clavicle (no statistical analyses were performed due to the small sample size).
Conclusion
DSX imaging is a promising tool for evaluating potential in vivo kinematic abnormalities in the ACJ during muscle-driven activities, laying the groundwork for further investigations in both ACJ-reconstructed and nonreconstructed patients. This study furnished essential data for conducting power analyses and designing future studies with an adequate sample size to investigate the impact of different treatment approaches on shoulder girdle mechanics.
Clinical Relevance
With its potential for accurately characterizing shoulder girdle kinematics post-ACJ injury, DSX imaging can offer valuable insights for future clinical studies, facilitating informed decisions regarding the short- and long-term impacts of treatment choices on shoulder health and function.
O conhecimento do exato papel da escápula em relação à função do membro superior é de extrema importância para compreensão do movimento humano, assim como, para entendermos as conseqüências e os motivos das alterações em seu padrão de normalidade. Neste sentido, muitos trabalhos vêm sendo realizados visando esclarecer o padrão de movimento normal, as estruturas que estão relacionadas a este padrão e as possíveis causas das disfunções, além de investigar as implicações causadas por tais disfunções em outras estruturas; entretanto, tais idéias são apresentadas de maneira fragmentada. Assim, a proposta do presente estudo é realizar uma revisão da literatura sobre a função da escápula e suas alterações na disfunção. Para isso, foi realizada uma busca na base de dados da PubMed por “scapulohumeral rhythm”, “scapular motion” e “scapular disfunction”, onde foram selecionados artigos entre 2000 e 2006. Os artigos selecionados foram analisados a fim de relacionar as evidências encontradas em uma idéia global. Nota-se que uma série de estruturas necessitam estar em pleno equilíbrio para manter o padrão cinético e cinemático normal. Uma alteração cinética geralmente acaba promovendo uma alteração cinemática, da mesma forma que a alteração cinemática impõe grande influência para promover uma alteração cinética. Desta forma, deve-se realizar uma avaliação minuciosa levando em consideração tanto os aspectos cinéticos quanto cinemáticos, porque só assim se consegue o equilíbrio necessário para a função normal do membro superior.
The human shoulder complex's motion is modeled by nine rotational degrees of freedom (DoF) at the sternoclavicular (SC), acromioclavicular (AC), and glenohumeral joints. Non-invasive measurement of these rotations is desirable for shoulder kinematic assessment or musculoskeletal modeling. Accuracy of the conventional method for estimating SC posterior rotation is unclear and might be overestimated because it assumes no rotation in the AC joint. We aimed to explore whether our new method, allowing AC rotation, provides a more accurate estimation of SC posterior rotation than the conventional method. We compared estimates by both methods, in 18 postures among 8 healthy men, with those measured by the registration method from magnetic resonance images. Posthoc analyses showed significant differences between the registration and conventional methods in all 18 postures and in only one posture when compared to our method. While the conventional method tended toward overestimation and showed a 22.7° root-mean-square error for all postures, the new method had greater accuracy (6.8° root-mean-square error). By combining this method with the scapulothoracic rotation measurement method and other traditional methods, it should be possible to indirectly measure 3-DoF AC rotation, implying that non-invasive measurement of all 9-DoF rotations of the shoulder complex would now be possible.
Scapular dyskinesis, the impairment of optimal scapular position and motion, is common in association with shoulder injury. A comprehensive evaluation process can show the causative factors and lead to effective treatment protocols. The complexity of scapular motion and the integrated relationship between the scapula, humerus, trunk, and legs suggest a need to develop rehabilitation programs that involve all segments working as a unit rather than isolated components. This is best accomplished with an integrated rehabilitation approach that includes rectifying deficits in mobility, strength, and motor control but not overtly focusing on any one area.
In order for correct shoulder function to occur, the scapula plays a number of responsibilities. These functions include synchronous scapular rotation during humeral motion, providing a stable basis for rotator cuff activation, and acting as a kinetic chain link. Scapular dyskinesis is defined as a change in the resting or dynamic position of the scapula. Scapular dyskinesis is a nonspecific response to a painful shoulder ailment rather than a specific response to glenohumeral pathology. Visual assessment of the scapular position at rest and during dynamic humeral motions, as well as objective posture measurements and scapular corrective techniques, is used to diagnose scapular dyskinesis. Treatment for scapular dyskinesis focuses on improving dynamic scapular stability by improving the motor control and strength of scapular stabilizers, as well as the flexibility of tight muscles and other connective tissues.
Background
Kinematics is studied by practitioners and researchers in different fields of practice. It is therefore critically important to adhere to a taxonomy that explicitly describes positions and movements. However, current representation methods such as cardan and Euler angles fail to report shoulder angles in a way that is easily and correctly interpreted by practitioners, and that is free from numerical instability such as gimbal lock.
Methods
In this paper, we comprehensively describe the recent Tilt-and-Torsion method and compare it to the Euler YXY method currently recommended by the International Society of Biomechanics. While using the same three rotations (plane of elevation, elevation, humeral rotation), the Tilt-and-Torsion method reports humeral rotation independently from the plane of elevation. We assess how it can be used to describe shoulder angles (1) in a simulated assessment of humeral rotation with the arm at the side, which constitutes a gimbal lock position, and (2) during an experimental functional task, with 10 wheelchair basketball athletes who sprint in straight line using a sports wheelchair.
Findings
In the simulated gimbal lock experiment, the Tilt-and-Torsion method provided both humeral elevation and rotation measurements, contrary to the Euler YXY method. During the wheelchair sprints, humeral rotation ranged from 14° (externally) to 13° (internally), which is consistent with typical maximal ranges of humeral rotation, compared to 65° to 50° with the Euler YXY method.
Interpretation
Based on our results, we recommend that shoulder angles be expressed using Tilt-and-Torsion angles instead of Euler YXY.
Introduction:
Manual wheelchair propulsion is a physically demanding task associated with upper extremity pain and pathology. Shoulder pain is reported in over 25% of pediatric manual wheelchairs users, and this number rises over the lifespan. Upper extremity biomechanics in adults has been associated with shoulder pain and pathology; however, few studies have investigated upper extremity joint dynamics in children. Furthermore, sex may be a critical factor that is currently unexplored with regard to pediatric wheelchair mobility.
Objectives:
To investigate differences in upper extremity joint dynamics between pediatric male and female manual wheelchair users with spinal cord injury (SCI) during wheelchair propulsion.
Methods:
Novel instrumented wheelchair hand-rims synchronized with optical motion capture were used to acquire upper extremity joint dynamics of 20 pediatric manual wheelchair users with SCI (11 males, 9 females). Thorax, sternoclavicular, acromioclavicular, glenohumeral, elbow, and wrist joint kinematics and kinetics were calculated during wheelchair propulsion. Linear mixed models were used to assess differences between sexes.
Results:
Females exhibited significantly greater peak forearm pronation (p = .007), normalized wrist lateral force (p = .03), and normalized elbow posterior force (p = .04) than males. Males exhibited significantly greater peak sternoclavicular joint retraction (p < .001) than females. No significant differences between males and females were observed for the glenohumeral joint (p > .012).
Conclusion:
This study found significant differences in upper extremity joint dynamics between sexes during manual wheelchair propulsion. Our results underscore the importance of considering sex when evaluating pediatric wheelchair mobility and developing comprehensive wheelchair training interventions for early detection and prevention of upper extremity pain and pathology.
Objective
This study aimed to directly and accurately measure the range of motion of the acromioclavicular joint through 3D reconstruction and image registration.
Methods
Thirteen healthy volunteers participated in the study. Computerized tomography (CT) was used to measure the acromioclavicular joint in four different motion poses. The images were integrated using reconstruction and registration technology, and the rotation angle range of the acromioclavicular joint was measured using 3D reconstruction. The measurements were expressed by axial angle representation. The dominant and the non-dominant sides were compared, and the difference in the axial angle of the acromioclavicular joint was compared in different postures.
Results
The difference between the dominant and non-dominant sides in acromioclavicular motion was not significant. In the sagittal motion of the upper limb, the rotation angle of the acromioclavicular joint was greatest in a resting horizontal position, with an average of 26.1°. In this position, 34.6% of flexion and extension movements of the upper limb were completed by the acromioclavicular joint, which was the highest level of engagement. The rotation angle was lowest in the resting posteroinferior position, with an average of 8.2°. In this position, 24.9% of the flexion and extension movements of the upper limb were completed by the acromioclavicular joint.
Conclusion
Combining 3D reconstruction and image registration is a direct and accurate method of measuring the motion of the acromioclavicular joint. The rotational motions of the acromioclavicular joint are bilaterally symmetrical and can be used as a reference for comparative study. The maximum range of motion of the acromioclavicular joint during rotation was found in the resting horizontal position. The clinical examination and post-treatment evaluation of the acromioclavicular joint’s rotation function can therefore be targeted in this range.
Objective:
This study aims to accurately measure the range of motion of the sternoclavicular (SC) joint using 3D reconstruction and image registration. The motion of the SC joint is analyzed by means of axial angle representation to identify the kinematical characteristics of this joint.
Methods:
A total of 13 healthy volunteers were enrolled in the study. The limit postures of four SC joint movements were scanned by computerized tomography. The images were integrated with reconstruction and registration techniques. The range of motion of the SC joint was measured using 3D modelling. The axial angle was used to indicate the range of motion of the SC joint. The difference between the dominant side and non-dominant side was compared and the differences in axial angle of the SC joint in different postures were compared.
Results:
The active axial angle of the SC joint on the dominant side was approximately 1∘ higher than that of the non-dominant side when the upper limb moved from a rest position to a posteroinferior position. In the sagittal motion of the upper limbs, the axial angle of the SC joint was greatest when moving from a horizontal position to a posterosuperior position, with an average of 23.55∘. Of the flexion and extension movements of the upper limbs from a rest position to a horizontal position, 13.66% (the smallest proportion) were completed by the SC joint.
Conclusion:
The combination of 3D reconstruction and image registration is a direct and accurate method of measuring the motion of the SC joint. Axial angle representation is an intuitive method of expressing rotation in a 3D space that allows for more convenient comparison; it is also more in line with the characteristics of human anatomy and kinesiology and therefore more accurately reflects the characteristics of joint motion. It is therefore useful for guiding clinical practice. In a physical examination, the extension of the upper limb from the horizontal position to the posterosuperior position and from the rest position to the posteroinferior position can best reflect the rotation function of the SC joint in the combined motion of shoulder joints.
Background and purpose: Following a stroke, three-dimensional clavicular/scapular/humeral joint rotations may become restricted and contribute to post-stroke shoulder pain. This study examined whether a treatment group provided with current standard treatment plus the proposed “Three-dimensional Shoulder Pain Alignment” mobilization protocol demonstrated improved pain-free shoulder range, functional reach and sleep compared to a control group provided with standard treatment alone.
Methods: In this double-blinded parallel-group randomized control trial, treatment and control subjects with moderate/severe post-stroke upper extremity impairment and shoulder pain were treated 3x/week for 4 weeks. Outcome measures included changes in pain-free three-dimensional clavicular/scapular/humeral range (using computerized digitization), pain during sleep and functional reach (using the Pain Intensity-Numerical Rating Scale), and pain location/prognostic indicators (using the Chedoke-McMaster Stroke Assessment-Shoulder Pain Inventory).
Results: Compared to controls (n = 10) the treatment group (n = 10) demonstrated significantly improved three-dimensional clavicular/scapular/humeral pain-free range during shoulder flexion and abduction (p < 0.05; Hedges g > 0.80), large effect sizes for decreased pain during sleep and functional reach to the head and back (OR range: 5.44-21.00), and moderate effect size for improved pain/prognostic indicators (OR = 3.86).
Conclusions: The Three-Dimensional Shoulder Pain Alignment mobilization protocol significantly improved pain-free range of motion, functional reach and pain during sleep in shoulders with moderate/severe post-stroke upper-extremity impairment.
• Implications for rehabilitation
• Although three-dimensional clavicular/scapular/humeral rotations are an essential component of normal pain-free shoulder range of motion, current guidelines for treatment of post-stroke shoulder pain only includes uni-dimensional mobilizations for joint alignment and pain management.
• The Three-Dimensional Shoulder Pain Alignment (3D-SPA) mobilization protocol incorporates multi-dimensional mobilizations in various planes of shoulder movement.
• The current study results demonstrate proof-of-concept regarding the 3D-SPA mobilization, and this approach should be considered as an alternative to the uni-dimensional mobilizations currently used in clinical treatment guidelines for post-stroke shoulder pain.
Videogrammetry is commonly used to record upper limb motions. However, it cannot track the glenohumeral joint center (GH). GH is required to reconstruct upper limb motions. Therefore, it is often estimated by separately measuring scapular motions using scapular kinematics measurements devices (SKMD). Applications of SKMD are neither straightforward nor always noninvasive. Therefore, this work investigates the feasibility of an alternative method to estimate GH from videogrammetry using a CT/MRI image of subject’s glenohumeral joint and without requiring SKMD. In order to evaluate the method’s accuracy, its GH estimations were compared to reference GH trajectories. The method was also applied to estimate scapular configurations and reconstruct an abduction motion measured by videogrammetry. The accuracy of GH estimations were within 5 mm, and the reconstructed motion was in good agreement with reported in vivo measurements.
Scapular dyskinesia refers to altered scapular motion or position. Specifically, it may include static or dynamic medial border prominence of the scapula, inferior angle prominence and/or premature elevation of the scapular, and accelerated inferior scapular rotation while lowering the arm. It generally occurs due to muscle imbalance/weakness or as a response to shoulder injury—including glenohumeral instability. Prevalence of scapular dyskinesis is 61% in overhead athletes and 33% in non-overhead athletes. Assessment should include a detailed physical examination including scapula-specific tests: the scapular assistance test (SAT) and scapular retraction test (SRT). Investigations (imaging and nerve conduction studies) should be targeted to identify any underlying shoulder pathology that may be a cause of dyskinesis. The mainstay of treatment for scapular dyskinesis is appropriate treatment of the underlying cause, followed by a supervised physiotherapy program focusing on re-establishing normal scapular motion and stability.
The ideal graft should have a high rate of integration, a low resorption rate, and a low risk of hardware fixation complications, and it should prevent the progression of osteoarthritis secondary to instability. Glenoid bone grafting techniques are necessary for restoring glenoid width and for preventing instability recurrence, while humeral grafting is used in order to treat symptomatic engaging Hill-Sachs lesions. Coracoid transfer procedures are described along with the more recent autograft techniques by means of the corticocancellous iliac crest bone, the distal clavicle, and the allografts from fresh-frozen femoral or humeral head and from the talus. The complications related to graft resorption are a current limitation of grafting technologies. New perspectives in bone grafting technologies come from the field of the basic science in the form of growth factor-infused bioscaffolds and of engineered functional bio-scaffold ricapitulating endochondral ossification.
In this chapter, the bones, joints, and the muscles of the shoulder complex and their role in the shoulder function are discussed in detail. The specific aims of this chapter are to; describe the structures of the bones and joints of the shoulder complex, discuss the stability and instability, and normal and abnormal motion at each joint and the role of the individual yet interdependent joints to the overall motion of the shoulder complex, describe the characteristics of the shoulder muscles, and discuss their role and the effects of their impairments in the shoulder complex.
Purpose: Altered three-dimensional (3D) joint kinematics can contribute to shoulder pathology, including post-stroke shoulder pain. Reliable assessment methods enable comparative studies between asymptomatic shoulders of healthy subjects and painful shoulders of post-stroke subjects, and could inform treatment planning for post-stroke shoulder pain. The study purpose was to establish intra-rater test–retest reliability and within-subject repeatability of a palpation/digitization protocol, which assesses 3D clavicular/scapular/humeral rotations, in asymptomatic and painful post-stroke shoulders.
Methods: Repeated measurements of 3D clavicular/scapular/humeral joint/segment rotations were obtained using palpation/digitization in 32 asymptomatic and six painful post-stroke shoulders during four reaching postures (rest/flexion/abduction/external rotation). Intra-class correlation coefficients (ICCs), standard error of the measurement and 95% confidence intervals were calculated.
Results: All ICC values indicated high to very high test–retest reliability (≥0.70), with lower reliability for scapular anterior/posterior tilt during external rotation in asymptomatic subjects, and scapular medial/lateral rotation, humeral horizontal abduction/adduction and axial rotation during abduction in post-stroke subjects. All standard error of measurement values demonstrated within-subject repeatability error ≤5° for all clavicular/scapular/humeral joint/segment rotations (asymptomatic ≤3.75°; post-stroke ≤5.0°), except for humeral axial rotation (asymptomatic ≤5°; post-stroke ≤15°).
Conclusions: This noninvasive, clinically feasible palpation/digitization protocol was reliable and repeatable in asymptomatic shoulders, and in a smaller sample of painful post-stroke shoulders.
• Implications for Rehabilitation
• In the clinical setting, a reliable and repeatable noninvasive method for assessment of three-dimensional (3D) clavicular/scapular/humeral joint orientation and range of motion (ROM) is currently required.
• The established reliability and repeatability of this proposed palpation/digitization protocol will enable comparative 3D ROM studies between asymptomatic and post-stroke shoulders, which will further inform treatment planning.
• Intra-rater test–retest repeatability, which is measured by the standard error of the measure, indicates the range of error associated with a single test measure. Therefore, clinicians can use the standard error of the measure to determine the “true” differences between pre-treatment and post-treatment test scores.
Altered scapular motions premeditate shoulder impingement and other musculoskeletal disorders. Divergent experimental conditions in previous research precludes rigorous comparisons of non-invasive scapular tracking techniques. This study evaluated scapular orientation measurement methods across an expanded range of humeral postures. Scapular medial/lateral rotation, anterior/posterior tilt and protraction/retraction was measured using an acromion marker cluster (AMC), a scapular locator, and a reference stylus. Motion was captured using reflective markers on the upper body, as well as on the AMC, locator and stylus. A combination of 5 arm elevation angles, 3 arm elevation planes and 3 arm axial rotations was examined. Measurement method interacted with elevation angle and plane of elevation for all three scapular orientation directions (p < 0.01). Method of measurement interacted with axial rotation in anterior/posterior tilt and protraction/retraction (p < 0.01). The AMC had strong agreement with the reference stylus than the locator for the majority of humeral elevations, planes and axial rotations. The AMC underestimated lateral rotation, with the largest difference of ∼2° at 0° elevation. Both the locator and AMC overestimated posterior tilt at high arm elevation by up to 7.4°. Misestimations from using the locator could be enough to potentially obscure meaningful differences in scapular rotations.
Through the sternoclavicular (SC) and acromioclavicular (AC) joints, scapular position and motion play a critical role in overall shoulder function and dysfunction. The predominant SC joint motion during arm elevation is posterior long-axis rotation. Simultaneously, the SC joint retracts and undergoes a small amount of elevation. Synchronous to these SC joint motions, during arm elevation, the AC joint undergoes upward rotation and posterior tilt. In addition, the AC joint allows the scapula to remain stable on the curved thoracic surface by internally rotating during arm elevation. These SC and AC joint motions couple to produce overall scapular upward rotation, posterior tilt, and internal or external rotation motions on the thorax as the arm is elevated. From these normal motion patterns, a wide variety of position and motion abnormalities have been identified. These SC, AC, and scapular motion abnormalities have also been associated with a broad range of shoulder pathologies. Research studies are further beginning to assess the mechanical impact of scapular motion deviations.
The quantitative analysis of upper-extremity motion is a challenging task. A single, universally accepted methodology does not exist, but it is possible to define a standardized way to report a measurement protocol and to formulate recommendations on the most important aspect. The aim of this chapter is to provide such guidelines, addressing common issues such as joint modeling, scapula tracking, soft-tissue artifact compensation, and summary of results.
Background:
Patients with subacromial impingement were reported to show abnormal scapular positions during shoulder elevation. However, the relationship between the scapular positions and subacromial impingement is unclear. The purpose of this study was to biomechanically determine the effect of scapular position on subacromial contact behavior by using fresh frozen cadavers.
Methods:
The peak contact pressure on the coracoacromial arch was measured with a flexible tactile force sensor in 9 fresh frozen cadaver shoulders. The measurement was performed during passive glenohumeral elevation in the scapular plane ranging from 30° to 75°. The scapular downward and internal rotations and anterior tilt were simulated by tilting the scapula in 5° increments up to 20°. The measurement was also performed with combination of scapular downward and internal rotations and anterior tilt positions.
Results:
The peak contact pressure decreased linearly with anterior tilt, and a significant difference between neutral scapular position (1.06 ± 0.89 MPa) and anterior tilt by 20° (0.46 ± 0.18 MPa) was observed (P < .05). However, the scapular positioning in the other directions did not change the peak contact pressure significantly. Furthermore, any combination of abnormal scapular positions did not affect peak contact pressure significantly.
Conclusion:
Scapular anterior tilt decreased peak contact pressure during passive shoulder elevation. In addition, scapular downward and internal rotations had little effect on peak contact pressure. The abnormal scapular motion reported in previous studies might not be directly related to symptoms caused by subacromial impingement.
This was a dynamic fluoroscopic study of the moving shoulder. The findings form the Dynamic Abduction Study (in the scapular plane) were:-
1) The normal range of scapular rotation is 65 degrees.
2) The normal range of gleno-humeral movement is 100 degrees.
3) There is a linear relation between scapular rotation and glenohumeral movement except at full elevation when the last 10 degrees are almost pure scapular movement.
4)The pattern of movement going up and coming down is similar.
5) Abnormal scapulohumeral rhythm may be assessed using this study but only in one case was this not observed clinically prior to the study.
6) Reversed scapulohumeral rhythm can be measured and was found valuable in assessing the progress of stiff shoulders.
7) The humeral head excursion on the glenoid was large in young patients (<30 years; 10+ mm) but much less in the middle-aged (6 mm).
8) Following both Silastic cup interposition arthroplasty and Stanmore total shoulder arthroplasty there is a slightly improved range of movement almost entirely due to increased scapular rotation.
9) There is very obvious restriction of external rotation of the humerus following Stanmore total shoulder arthroplasty and this may be related to the poor range of glenohumeral movement (15 degrees) recorded during abduction.
Knowledge of the movement which occurs at the AC joint has been limited in the past because of inability to palpate or visualise the joint as the arm is elevated. Our work, although complex, is able to establish that movement of the AC joint is an important component of shoulder movement.
We studied the position and rotational changes associated with elevation of the glenohumeral joint, using a three-dimensional magnetic-field tracking system on nine fresh cadaveric shoulders. The plane of maximal arm elevation was shown to occur 23 degrees anterior to the plane of the scapula. Elevation in any plane anterior to the scapula required external humeral rotation, and maximal elevation was associated with approximately 35 degrees of external humeral rotation. Conversely, internal rotation was necessary for increased elevation posterior to the plane of the scapula. The observed effects of this rotation were to clear the humeral tuberosity from abutting beneath the acromion and to relax the inferior capsular ligamentous constraints. Measurement of the obligatory humeral rotation required for maximal elevation helps to explain the relationship of the limited elevation seen in adhesive capsulitis and after operations which limit external rotation.
The function of the shoulder is to position the arm with respect to the thorax. Humerothoracic positions are commonly described in terms of the degrees of humeral elevation in the sagittal plane (flexion) and/or the degrees of elevation in the coronal plane (abduction). This article proposes a more general system for describing positions of the arm based on the plane of humeral elevation and the angle of elevation within this plane. This system is used to present the humerothoracic positions used by eight normal subjects to perform several activities of daily living as well as those achieved in a range-of-motion examination of the shoulder. Eating, hair combing, and maximal elevation were all performed in a plane approximately 60° anterior to the coronal plane. Between reaching the perineum and washing the contralateral axilla, the humerus functioned in a range of planes extending over 180°.
It is critical that surgeons comprehend the normal laxity of the glenohumeral joint (1) to assist them in diagnosing conditions of clinical instability and (2) to help define a therapeutic end point for the management of shoulders with excessive stiffness. In clinical practice this joint laxity is judged by standard manual tests. We report a quantitative study of the clinical in vivo laxity of the normal shoulders of eight male volunteers. To our knowledge this is the first time that the laxity revealed on standard manual clinical tests has been quantified in vivo. The relative motions of the humerus and scapula were determined with an electromagnetic spatial tracker. This device was pinned percutaneously to the humerus and scapula of each of eight normal male volunteers of ages 25 to 45 years. An experienced shoulder surgeon carried out standard manual clinical tests of glenohumeral laxity while the resulting displacements of the humeral head relative to the glenoid were measured. Spatial tracker data indicated that for each of the different tests, the positions of the glenohumeral and scapulothoracic joints were reproducible for a given subject and among subjects. Substantial glenohumeral translations were measured during those manual laxity tests in which the joint was not at the limit of its range of motion: the drawer test, 7.8 ± 4.0 mm anterior and 7.9 ± 5.6 mm posterior; the sulcus test, 10.6 ± 3.8 mm inferior; and the push-pull test, 9.0 ± 6.3 mm posterior. A minimal translation of 0.3 ± 2.5 mm was measured during the fulcrum test in which the glenohumeral ligaments were under tension. The observed translations were reproducible in each subject's shoulder. On the other hand, there was marked variability among subjects. Even though manual laxity tests are a standard part of the clinical evaluation of the shoulder, our finding that normal glenohumeral joints show substantial translations indicates that translation on clinical manual laxity testing is not in and of itself a sufficient indication for surgical stabilization.
The purpose of this study was to determine the forces in the glenohumeral joint for isometric abduction (including all directions of rotation) in the plane of the scapula. The lines of actions of muscles were obtained from 3 upper quarter specimens, electromyographic data was used, as well as geometrical parameters of shoulder motion. The main assumption made in the analysis was that the force in a muscle was proportional to its area times the integrated electromyographic signal. The resultant force reached a maximum of 0.89 times body weight at 90 degrees of abduction, while the shearing component up the face of the glenoid was a maximum of 0.42 times body weight at 60 degrees of abduction.
A qualitative kinematical model for the shoulder complex in elevation is presented. The need for such a model was realised during the biomechanical assessment of the glenohumeral joint due to the inaccessibility of the shoulder region to the common methods of following bone movements. The shoulder complex is described as a two mechanism system, the first consisting of the skeleton, clavicle and scapula, and the second the scapula (or scapula plus clavicle) and humerus. Elevation of the arm is divided into four phases during which the scapula and clavicle behave intermittently as separate links and a structure. It is proposed that during the whole activity the serratus anterior lower acts as the prime mover of the shoulder girdle.
A method to investigate the rhythm of the human shoulder, i.e. the interplay between the motion of constituent parts of the shoulder, has been devised and tested. The method is based upon numerical evaluation of low dose roentgenstereophotogrammetric motion pictures of subjects equipped with radiation dense implantations in the bones. Evaluation of the method shows that it may be used in determining motion patterns and that the employed interpolation techniques can be used to simulate motions not actually performed in the laboratory. The shoulder rhythm has been previously poorly investigated and quantified results published pertain to one plane only. Our results on motion patterns correlate with previous investigations. With this method, we show that the absolute position of the bones varies significantly between individuals while the relative displacement of the bones during motion exhibit similarities. In particular the results show that, under normal conditions, the individual rhythm is very stable and insensitive to small hand-loads.
To help resolve longstanding uncertainties about kinematics of the shoulder, we studied three-dimensional glenohumeral joint motion during arm elevation. A magnetic tracking system was used to monitor the three-dimensional orientation of the humerus with respect to the scapula. Appropriate coordinate transformations were then performed for the calculation of glenohumeral joint rotation based on the defined Eulerian angle. The effects of the plane of elevation and the humeral rotation on the magnitude of arm elevation were documented. The maximum humeral elevation at the glenohumeral joint took place in a plane anterior to the scapular plane. Maximum elevation in all planes anterior to the scapular plane required external axial rotation of the humerus. Conversely, internal axial rotation was necessary for maximum elevation posterior to the scapular plane. Quantifying the obligatory axial rotation explains the relationship of internal and external rotation with maximum elevation.
In order to measure the three-dimensional (3D) position of the shoulder girdle bones, as well as the 3D positions of muscle attachments and joint surfaces in cadaver experiments, a measurement instrument, called the palpator, was developed. The palpator is composed of an open chain of four links connected by four hinges. By recording the rotation of the hinges using potentiometers, the position of the end-point of the palpator can be calculated. After the identification of 23 parameters of the palpator, a measurement accuracy of 1.43 mm is obtained.
We have demonstrated that certain passive motions of the glenohumeral joint are reproducibly accompanied by translation of the head of the humerus on the glenoid. We investigated the relationship of these translations to the position of the glenohumeral joint and to applied torques and forces in seven isolated glenohumeral joints from fresh cadavera, using a six-degrees-of-freedom position sensor and a six-axis force and torque transducer. Reproducible and significant translation occurred in an anterior direction with glenohumeral flexion and in a posterior direction with extension. We also observed translation with cross-body movement. The translation occurring with flexion was obligate in that it could not be prevented by the application of an oppositely directed force of thirty to forty newtons. Operative tightening of the posterior portion of the capsule increased the anterior translation on flexion and cross-body movement and caused it to occur earlier in the arc of motion compared with the intact glenohumeral joint. Operative tightening of the posterior part of the capsule also resulted in significant superior translation with flexion of the glenohumeral joint.
The effects and interaction of the anatomical displacements in the human knee are a prerequisite to an accurate assessment and communication of the kinematic data. For the kinematic information to be used to improve diagnosis and treatment, and for better prosthetic design and installation, there must be clear, concise, and universal definitions of the displacements. In general, the displacements are defined as three translations and three rotations. In this paper, anatomic landmarks on the femur and on the tibia are used to define the locations and orientations of the six displacement axes; i.e. three translational and three rotational displacement axes. The most commonly accepted kinematic representation of the knee joint, in the literature, is a special geometry three-cylindric open chain in which the axes of the cylindric joints are defined according to the rotational displacement axes. The sequentially adjacent joint axes are assumed to not only intersect but to intersect at right-angles. The open chain permits a total of six degrees of freedom between a Cartesian reference frame attached to the femur and a Cartesian reference frame attached to the tibia. In this paper, the three rotational axes are shown to be skewed and off-set from each other, therefore, a three-cylindric open chain with skewed joint axes is proposed to measure the six displacements between the two reference frames. The authors believe that the proposed open chain is the most general to date and provides a more realistic representation of the displacements in the knee. To illustrate the significance of the reference frames on the interpretation of measured data, the anterior/posterior drawer is plotted against per cent gait cycle for three existing open chains and the proposed open chain.
In many biomechanical motion studies, kinematic parameters are estimated from position measurements on a number of landmarks. In the present investigation, dummy motion experiments are performed in order to study the error dependence of kinematic parameters on geometric factors (number of markers, isotropic vs anisotropic landmark distributions, landmark distribution size), on kinematic factors (rotation step magnitude, the presence of translational displacements, the distance of the landmarks' mean position to the rotation axis), and on anisotropically distributed measurement errors. The experimental results are compared with theoretical predictions of a previous error analysis assuming isotropic conditions for the measurement errors and for the spatial landmark distribution. In general, the experimental findings agree with the predictions of the error model. The kinematic parameters such as translations and rotations are well-determined by the model. In the helical motion description, the same applies for the finite rotation angle about and the finite shift along the helical axis. However, the direction and position of the helical axis are ill-determined. An anisotropic landmark distribution with relatively few markers located in the direction of the rotation axis will even aggravate the ill-posed nature of the finite helical axis estimation.
In this paper, individual joint sinus cones associated with the sternoclavicular, claviscapular, and glenohumeral joints of the three-dimensional kinematic model introduced in Part I for the human shoulder complex are quantitatively determined. First, mathematical description of the humerus orientation with respect to torso is given in terms of eight joint variables. Since the system is a kinematically redundant one, solution for the joint variables satisfying a prescribed humerus orientation is possible only if additional requirements are imposed; and the "minimum joint motion" criterion is introduced for this purpose. Two methods, namely the Lagrange multipliers and flexible tolerance methods, are formulated and tested for the optimization problem. The statistical in-vivo data base for the circumductory motion of the upper arm is employed to determine a set of joint variables via optimization, which are then utilized to establish the sizes and orientations of the elliptical cones for the individual joint sinuses. The results are discussed and compared with those given on the basis of measurements made on cadaveric specimens.
Modelling of the human shoulder complex is essential for the multi-segmented mathematical models as well as design of the shoulder mechanism of anthropometric dummies. In Part I of this paper a three-dimensional kinematic model is proposed by utilizing the concepts of kinematic links, joints, and joint sinuses. By assigning appropriate coordinate systems, parameters required for complete quantitative description of the proposed model are identified. The statistical in-vivo data base established by Engin and Chen (1986) is cast in a form compatible with the model by obtaining a set of unit vectors describing circumductory motion of the upper arm in a torso-fixed coordinate system. This set of unit vectors is then employed in determining the parameters of a composite shoulder complex sinus of a simplified version of the proposed model. Two methods, namely the flexible tolerance and the direct methods, are formulated and tested for the determination of an elliptical cone surface for a given set of generating unit vectors. Numerical results are presented for the apex angles and orientation of the composite joint sinus cone with respect to the anatomical directions.
The dynamic pattern of scapulohumeral rhythm and the scapular instantaneous center of rotation were studied in 20 healthy young male subjects. The most common pattern of scapulohumeral rhythm was characterized by three separate phases, with the greatest relative amount of scapular rotation occurring between 80 and 140 degrees of arm abduction. The scapular instantaneous center of rotation was observed to be located initially at, or near, the medial root of the scapular spine, and gradually migrated toward the region of the acromioclavicular joint as arm abduction progressed. A biomechanical model of the shoulder girdle was proposed by correlating the results from the present study with the electrical activity of the scapular rotators. This model is useful in demonstrating the true dynamic function of the muscles acting on the scapula as well as the mechanical efficiency of upward scapular rotation during arm abduction.
A technique enabling simultaneous visualisation of skin and underlying bony structures in the walking horse was used to quantify skin displacements on the lateral surface of carpal, tarsal and fetlock joints. The technique employed implanted light-emitting-diodes (LEDs) for marking the bone, and self adhesive spot labels for marking the overlying skin. Photographic recordings were made. Skin displacement was measured in six Dutch Warmblood horses. Mean total displacements and mean displacement per degree of change of joint angle were calculated. Displacements at the level of the fetlock joints appeared to be generally small (less than or equal to 2 mm), but displacements up to 2 cm were measured in the distal tibia. Displacements of this magnitude are of importance for the interpretation of results obtained by modern gait analysis techniques.
A magnetic position and orientation tracking system is currently available for the determination of the position and orientation of a sensor relative to a source by utilizing the principle of low-frequency magnetic field technology. The application of this system for biomechanical analysis of human movement is examined in this study. Studies of both planar particle motion and spatial rigid body motion based on Eulerian angle description and screw displacement axis description have been performed. The system has been found to be quite accurate and easy to use, and it would be a useful tool in kinesiologic research.
Two modified DLT algorithms are presented that improve the accuracy of three-dimensional object space reconstruction by almost an order of magnitude when compared with conventional methods. The improvement in the linear modified DLT (MDLT) algorithm is achieved by satisfying certain orthogonality conditions in the form of a non-linear constraint, thereby effectively eliminating a redundant DLT parameter. In the non-linear MDLT algorithm, the improvement and computational stability results from the appropriate elimination of implicit variables from one side of the approximating relations and the corresponding reformulation of the objective function to be minimized. The highest reconstruction accuracy of 0.733 mm rms mean error was obtained with the non-linear MDLT algorithm. This corresponds to a spatial resolution of about one part in 2860 or 0.035% overall accuracy. The accuracy obtainable with the linear MDLT was found to be slightly less and about 0.041% (0.833 mm rms mean error).
Effectiveness of the multi-segmented total-human-body models to predict realistically live human response depends heavily on the proper biomechanical description and simulation of the major articulating joints of the body. In these models, the most difficult and the least successful modelling of a joint has been the shoulder complex because of the lack of appropriate biomechanical data as well as the anatomical complexity of the region. This paper in Part I presents various aspects of a research program to collect three-dimensional kinematic data for the shoulder complex. A sonic digitizing technique which utilizes an overdeterminate number of sonic emitters on the moving body segment was used for the kinematics analysis. The numerical results are presented for three male subjects for their voluntary shoulder complex sinuses. The results are given in a locally-defined joint axis system as well as in the torso-fixed coordinate system in the form of globographic representation.
In mathematical modeling of multi-segmented articulating total-human-body, there is no doubt that the shoulder complex plays one of the most important roles. However, proper biomechanical passive resistive force data have been lacking in the literature. This paper presents determination of the three-dimensional passive resistive joint properties beyond the maximal voluntary shoulder complex sinus. A functional expansion with two spherical angular variables in the local joint axis system is proposed to fit the overall restoring force (moment) data. A constant restoring force (moment) contour map as well as a three-dimensional perspective view of the results are presented in a new coordinate system defined in this study. Finally, a statistical data base is established by utilizing the statistical analysis procedures discussed in Part I of this paper.
In the last two decades, several multi-segmented mathematical models of the total-human-body have appeared in the literature. While these models can handle very sophisticated load-motion situations, their effectiveness depends heavily on the proper biomechanical description and simulation of the major articulating joints of the human body. Among these joints, the most complicated and the least successfully modeled one has been the shoulder complex mainly due to the lack of an appropriate biomechanical data base as well as the anatomical complexity of the shoulder region. In 1984, the senior author and his associates proposed a new kinematic data collection methodology by means of sonic emitters and associated data analysis technique. Based on this data collection methodology, Part I of this paper establishes a statistical data base for the shoulder complex sinus of the male population of ages 18-32. Estimates for the population mean and standard deviation as well as their confidence intervals are presented. The results are expressed in functional expansion form relative to a locally defined joint axis system as well as relative to the torso-fixed coordinate system in the form of globographic representation.
The finite element method described in this study provides an easy method to simulate the kinetics of multibody mechanisms. It is used in order to develop a musculoskeletal model of the shoulder mechanism. Each relevant morphological structure has been represented by an appropriate element. For the shoulder mechanism two special-purpose elements have been developed: a SURFACE element representing the scapulothoracic gliding plane and a CURVED-TRUSS element to represent muscles which are wrapped around bony contours. The model contains four bones, three joints, three extracapsular ligaments, the scapulothoracic gliding plane and 20 muscles and muscle parts. In the model, input variables are the positions of the shoulder girdle and humerus and the external load on the humerus. Output variables are muscles forces subject to an optimization procedure in which the mechanical stability of the glenohumeral joint is one of the constraints. Four different optimization criteria are compared. For 12 muscles, surface EMG is used to verify the model. Since the optimum muscle length and force-length relationship are unknown, and since maximal EMG amplitude is length dependent, verification is only possible in a qualitative sense. Nevertheless, it is concluded that a detailed model of the shoulder mechanism has been developed which provides good insight into the function of morphological structures.
A finite element musculoskeletal model of the shoulder mechanism consisting of the thorax, clavicula, scapula and humerus has been used for analysis of the kinematic and dynamic behavior. The model includes 16 muscles, three joints, three extracapsular ligaments and the motion constraints of the scapulothoracic gliding plane which turns the shoulder girdle into a closed-chain mechanism. Simulations are inverse dynamic. Input variables are the positions of the shoulder girdle and humerus which have been recorded in 10 subjects during unloaded and loaded humeral abduction and anteflexion. Comparisons of muscle force predictions and EMG recordings are hampered by the unknown force-length relationship and the length dependency of EMG amplitude. It is concluded that EMG amplitude cannot be used for validation of complex musculoskeletal models. Muscle function is analyzed with help of a force and moment balance of the three joints. The moment balance includes the contributions of ligaments and the reaction forces at the scapulothoracic gliding plane. The scapulothoracic gliding plane is very important for the motions and the stabilization of the shoulder girdle. The direction and magnitude of joint reaction forces are calculated as well. It is concluded that the model provides good insight into the mechanics of the shoulder mechanism and that it enables an analysis of the function of morphological structures.
1. Screw fixation of clavicle to coracoid process, with subsequent calcification and ossification along the conoid and trapezoid ligaments, creates an extra-articular fusion of the acromio-clavicular joint.
2. Though the follow-up is admittedly early, excellent results can be obtained in the young healthy adult. It is possible to return an athlete to competitive sports and a heavy labourer to full work in a surprisingly short time.
3. The operation is of doubtful value in older patients.
4. A precise operative technique is most important in producing a successful result.
5. Screw fixation introduces a new movement into the abduction mechanism of the shoulder: synchronous scapulo-clavicular rotation.
Dislocations About the Shoulder
- C A Rockwood
Theory of Shoulder Mechanism: Descriptive and Applied
- A K Saha
Beitra¨ge zur Lehre von dem Mechanismus der Bewegungen des Schultergu¨rtels
- Steinhausen
Observations on the Function of the Shoulder Joint
- V T Inman
- Abbottl B C Saundersj
The Biomechanical Definition of the Motions of the Shoulder Girdle Bones
- G M Pronk
The Modelling of the Scapulothoracic Wall
- G M Pronk
- A Padt
- Van Der
Changes of the Tilting Angle of the Scapula Following Elevation of the Arm
- M Kondo
- S Tazoe
- M Yamada